1. Field of the Invention
The presently invention pertains to seismic data interpretation and, more particularly, with respect to near-surface geological structures.
2. Description of the Related Art
This section of this document introduces various aspects of the art that may be related to various aspects of the present invention described and/or claimed below. It provides background information to facilitate a better understanding of the various aspects of the present invention. As the section's title implies, this is a discussion of “related” art. That such art is related in no way implies that it is also “prior” art. The related art may or may not be prior art. The discussion in this section of this document is to be read in this light, and not as admissions of prior art.
Much effort is expended in locating, evaluating, and exploiting hydrocarbon deposits, e.g., oil and natural gas, trapped in subterranean geological formations. The exercise of examining subterranean geological formations for deposits of hydrocarbon deposits is known as “seismic surveying” or, sometimes, “geophysical surveying”. It is highly desirable to locate hydrocarbon deposits in reservoirs in the subsurface from which liquid or gas can be extracted or into which liquid or gas can be injected.
A seismic survey typically involves deploying seismic source(s) and seismic sensors at predetermined locations. The sources generate seismic waves which propagate into the geological formations creating pressure changes and vibrations along their way. Changes in elastic properties of the geological formation scatter the seismic waves, changing their direction of propagation and other properties. Part of the energy emitted by the sources reaches the seismic sensors. Some seismic sensors are sensitive to pressure changes (hydrophones), others to particle motion (geophones), and industrial surveys may deploy only one type of sensors or both. In response to the detected waves, the sensors generate electrical signals to produce seismic data. Analysis of the seismic data can then indicate the presence or absence of probable locations of hydrocarbon deposits.
The correlation of surface geomorphology with subsurface geology is well known. Huggett, R. J. Fundamentals of Geomorphology (2nd ed., Routledge Fundamentals of Physical Geography, Routledge, London 2007). Shallow geologic formations, or “near-surface geological structures”, are therefore of interest. Those in the art will appreciate that the term “near-surface” is a term of art commonly used and well understood in the art. They can therefore identify those geological structures that are “near-surface” and those that are not.
Near-surface geological structures present particular problems not encountered with deeper formations. Mapping near-surface geological structures with seismic data acquired by state-of-the-art receiver arrays is often compromised by noise resulting from near-offset source noise and seismic near-field effects up to the degree that the data cannot be used for shallow structural mapping at all. In cases where the data is noisy but usable, conventional techniques addressing this problem using a variety of processing techniques that remove noise from the data prior to interpreting the data. However, the industry continues to seek better approaches to this problem.
The present invention is directed to resolving, or at least reducing, one or all of the problems mentioned above.